Field
Embodiments of the present disclosure relate to apparatus and methods for processing semiconductor substrates. More particularly, embodiments of the present disclosure relate to apparatus and methods for monitoring one or more parameters at various locations in a processing chamber.
Description of the Related Art
During manufacturing of semiconductor devices, a substrate is usually processed in a processing chamber, where deposition, etching, thermal processing may be performed to the substrate. When a process requires the substrate being processed to be heated to and/or maintained at certain temperatures, a substrate support assembly including one or more heaters may be used. However, as the size of the substrate being processed increases, it becomes challenging to maintain uniform temperature across the substrate support and the substrate because temperatures at various locations, such as at various radii of the substrate support, may be different. Traditionally, infrared sensors positioned through optical windows are used to measure temperatures at various locations. However, infrared sensor systems are not only expensive but also not dependable because the accuracy strongly depends on emissivity of components being measured which changes over time. Other solutions, such as using multiple thermal sensors embedded in the substrate support and monitoring electrical resistivity of one or more heating elements, may be impractical or not suitable for some ranges of processing temperatures.
Therefore, there is a need for apparatus and methods for improved monitoring temperature or other process parameters at various locations of a substrate support.